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Soldering

Discussion in 'General Electronics Discussion' started by hyudryu, Mar 10, 2010.

  1. hyudryu

    hyudryu

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    Feb 24, 2010
    Can anyone tell me what the difference between unleaded solder and leaded solder is? Why would they even want to put lead in a product that does not NEED lead?:confused: Does it make it better?
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
  3. hyudryu

    hyudryu

    64
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    Feb 24, 2010
    Thanks but i am having trouble soldering onto a Darlington Power transistor because that type of metal is solder repellent? I can't seem to get the solder to stick. Even if i surround the whole thing with a big blob of solder, i end up burning it out. How do i solder onto it?
     
  4. Mitchekj

    Mitchekj

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    Jan 24, 2010
    Is this the TO-3 package thing again? I still believe you are not applying enough heat. If you're killing the transistors, then you are using just enough heat for a long enough period to do so. You'll need high heat, over a short period of time to get the solder to wet properly. If you're on the component with the iron for more than 5-10 seconds, you're doing it wrong.

    I ask again: what type of iron are you using? You may need a larger, screwdriver type tip at 720+ degrees F or so. Is this a 'plug into the wall' pencil-only type deal? Are you using a little conical tip? Those probably won't work very well, with any amount of time or effort. I assure you, the package is not "solder repellant." It's just doing it's job by sinking the heat away, being a high power device and all.

    Other than that, have you considered getting the same thing in a TO-220 package? Have you considered the need to heat sink this component when in use? I am quite certain it will get very hot (and die) if you approach moderate-high power levels and not heat sink it.

    As to Pb / Pb-free solder, the link posted above will tell you everything you'd ever want to know. :)

    Edit: Oh yeah, and flux. lol. Make sure you're using flux (either dab it on, or use rosin-core solder with a flux core. Larger diameter stuff may help.)
     
    Last edited: Mar 11, 2010
  5. davenn

    davenn Moderator

    13,293
    1,757
    Sep 5, 2009
    If this is a TO3 cased transistor .... you shouldnt even be trying to solder to the case
    anyway!!!

    you should be mounting the transistor onto an appropriate heatsink and have solder
    lug(s) under one of the screws/nuts and solder onto that solder lug then there will be
    absolutely no problem with soldering any connections to the transistor :)

    cheers
    Dave
    VK2TDN
     
  6. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,191
    2,693
    Jan 21, 2010
    Apart from requiring enough heat and flux, it may be worth cleaning the leads of the transistor with an ink eraser (slice the end of it, place the lead in the slice and move up and down).

    I hope you're not trying to solder onto the body of the transistor. The connection to the body is usually made mechanically (i.e. through one of the attachment bolts).
     
  7. Mitchekj

    Mitchekj

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    Jan 24, 2010
    Reading his gauss gun thread, the right way seemed harder, hehe.
     
  8. hyudryu

    hyudryu

    64
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    Feb 24, 2010
    Ha i am thinking on using a thyristor 2N6504 it can withstand 300A 800V surge and i lowered my capacitance to around 1000 uF.
    I need some suggestions for solder brands. I recently found old solder that has been lying in my toolbox for i think 7 years. Today i used it and when i used it, it was better than any solder i used:eek:! It is some triple core rosin solder and when you solder on a pcb, the flux actually bubbles and surrounds the pcb to prevent shorting when i solder onto an ic socket. Do you know if the bubbly thing is flux? I have used some flux core rosin solder but there is no bubbles. It just smokes a LOT and no surrounding flux or anything

    Someone help me because i can't find the 2N6504. Are there any electronical sites you would like to suggest to me?
     
    Last edited: Mar 12, 2010
  9. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,191
    2,693
    Jan 21, 2010
    Check again, the 2N6504 is a 50V rated device. You'd be looking for a 2N6507, 2N6508, or 2N6509.

    In another of your threads I made some observations of what I *think* you're doing. 1000uF of the capacitors I think you have would be easily capable of supplying more than 300A. My rough guess would be that 600A would be a ballpark figure, but it could conceivably exceed that by some margin.
     
  10. hyudryu

    hyudryu

    64
    0
    Feb 24, 2010
    Yes but i measured my coil and it is 1.3 ohms and i figured it would take up some current for the magnetic flux so it probably wont be 600A. But to be safe, i will solder 3 of them parallel so it won't burn out.
    For the 2N6504 when i googled it, the datasheet was 50V 300A surge... does the 2N6508 have a 300A surge also?For my capacitors, they drain pretty fast. when i connect wires, the wires melt onto each other and the power drains all in a few milliseconds
    And should i use lead solder? I read today that lead solder creates lead oxide gas which can give you lead poisoning. I made a fume extractor but i still dont want to risk it. Is it safe? So first, i got a laptop fan, i put pet store bought active carbon rocks and i put them inside a sack and put it at the end of the fan so the air goes through the active carbon. I tried lighting a match and it filtered out about 70-83.5% of the smoke.


    1 more question, If i bought a sealed lead acid battery that is 5AH and is at 2V. How do i charge it? Do i just turn the voltage to 2V on my power supply and plug it on? + to + and - to -?
     
    Last edited: Mar 12, 2010
  11. Mitchekj

    Mitchekj

    288
    0
    Jan 24, 2010
    "...the flux actually bubbles and surrounds the pcb to prevent shorting..."

    Flux is not intended to be used as a dielectric. The more I read, the more I don't believe it's a good idea that you do this. I'm getting visuals in my head of this thing dangling by tiny wires, turning orange-red.

    That said, do it as mentioned above: mount it properly.
     
  12. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,191
    2,693
    Jan 21, 2010
    Use ohms law to calculate the maximum current. For 300V and 1.3 ohms what is that?

    Have you measured the inductance of the coil? Will it saturate at a current less than the maximum allowed by the resistance of the coil? Given the charge stored in the capacitor, the resistance of the coil and its inductance, how fast will the current rise, and what will its peak value be?

    You need to be able to answer most (if not all) of these questions.

    It doesn't work that way. You can almost guarantee that one device will hog all of the current. The other problem is triggering all of the devices at *exactly* the same time.

    You're better off with a device that can handle the current. I'd be looking at something more like this http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=ST230C04C0-ND

    How did you measure the discharge time?

    From that time, how did you calculate the current?

    87.93% of statistics are made up.

    Don't worry too much about lead poisoning from leaded solder. Most of the smoke is the flux and it's visible. Just work in a ventilated place.


    kinda... Look up the specs for the battery.

    For a given temperature it will specify a charging voltage and current. Set your power supply to that voltage (it may be 2.35V) and set the current limit to a value no greater than the charge current. The battery will initially charge at the current you have set your PSU to and eventually this will reduce as the voltage on the battery rises.

    Beware of any charging restrictions that may apply (see the data sheet)

    If your power supply does not have a current limit (not a rating, a variable current limit) then you can manually adjust the voltage to achieve a suitable charge rate, but it's a tedious process, prone to error, and not recommended.
     
  13. 55pilot

    55pilot

    434
    3
    Feb 23, 2010
    You shouldn't have to worry about that. Lead poising takes time to kill. The way you are going, this project is likely to kill you long before the lead does.

    ---55p
     
  14. neon

    neon

    1,325
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    Oct 21, 2006
    THE CASE IS ALUMINUM so it cannot be soldered but it can be brazen
     
  15. Resqueline

    Resqueline

    2,848
    1
    Jul 31, 2009
    Sigh.. Some cases are indeed aluminum, and some are steel. Aluminum can be soldered with the proper flux, but the heat might kill the chip (not to mention brazing).
    Either way TO-3 cases (which I believe is the case here) are not meant to be soldered, and I fail to see the problem in simply using a nut and a screw to make a connection..
     
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